It has heretofore been proposed to ignite explosives by transmitting laser energy to an initiator along one or more optical fibers. One problem that arises in systems of this character involves the desired ability to test continuity and integrity of the laser-fiber-initiator light path in situ and without igniting the explosive. Another problem involves controlled sequential ignition of a plurality of explosives within a short time frame. For example, it is desirable to possess the ability to ignite multiple initiators within one millisecond. However, motor-driven mirrors and the like heretofore proposed have been characterized by switching times on the order of two milliseconds or more, and thus have not been able to obtain substantially simultaneous ignition of multiple initiators within the short time frame specified.
It is a general object of the present invention to provide an initiator and system of the described character that include facility for rapid and efficient self-test of the laser-fiber-initiator light path at will, in situ and without risk of igniting the explosive charge. Another object of the invention is to provide an initiator and system of the described character in which the continuity and integrity self-test can be rapidly performed immediately prior to and without interfering with explosive ignition.
Another object of the present invention is to provide a laser explosive ignition system of the described character in which a plurality of explosive devices may be individually ignited from a single laser source substantially simultaneously, which is to say within a prespecified short time duration such as one millisecond.